1. Field of the Invention
The invention relates to a vehicle equipment mounting structure that arranges a motor case, in which a rotary electric machine that drives a vehicle is housed, in a compartment provided forward of a vehicle cabin, and that mounts a power control apparatus that controls the rotary electric machine, and an auxiliary battery that supplies electric power to a control portion of the power control apparatus.
2. Description of Related Art
Electric vehicles in which the vehicle is driven by driving force from a rotary electric machine such as a motor-generator, hybrid vehicles in which the vehicle is driven by a combination of a rotary electric machine and an engine that is an internal combustion engine, and fuel cell vehicles in which the vehicle is driven by electric power generated by a fuel cell, and the like are known. These kinds of vehicles are equipped with a power control apparatus that receives a supply of electric power from a main battery or a fuel cell, and has a step up converter and inverter and the like that control the electric power to a motor-generator (hereinafter, also referred to as “motor”).
The power control apparatus is also referred to as a PCU (power control unit), and must be mounted in an engine compartment that is close to the motor-generator in order to handle the high voltage and high current. Therefore, in a hybrid vehicle in which the engine is started by the motor-generator, an auxiliary battery for starting the engine is arranged in the luggage compartment because it does not need to be arranged near the engine, as well as for reasons related to space in the engine compartment. In recent years, high-voltage equipment is being made smaller and smaller, so the auxiliary battery is now able to be arranged inside the engine compartment and near the power control apparatus. As a result, a cable that had to be brought around to the luggage compartment can be reduced, thereby enabling both weight and cost to be reduced.
However, when the auxiliary battery is arranged near the power control apparatus, it is preferable to avoid interference between the auxiliary battery and power control apparatus in order to quickly and efficiently protect and rapidly discharge the power control apparatus when the vehicle is involved in a collision. Also, although there would be little harm from damage to the auxiliary battery because it is a relatively low voltage of only 12 volts, it is desirable to keep damage to the electric power apparatus that controls high voltage of several hundred volts to a minimum.
Therefore, technology described in Japanese Patent Application Publication No. 2002-362254 (JP-A-2002-362254) has a detachable mechanism in which, when the vehicle is involved in a collision, a relay box moves upward and detaches from a vehicle body in response to a load transmitted from an auxiliary battery via a guide surface when the auxiliary battery moves to the rear as a result of a barrier (i.e., an obstacle) penetrating the vehicle. The battery moves smoothly toward the rear by this mechanism. Providing this kind of detachable structure for the relay box makes it possible to improve the impact absorption performance by preventing interference between vehicle equipment and other members that move by the impact of a collision. Japanese Patent Application Publication No. 2010-158991 (JP-A-2010-158991) describes an equipment mounting structure that mounts a front end of a power control apparatus in a position farther back toward the rear of the vehicle than a front end of a motor case, and that arranges an electric compressor on the vehicle rear side of the power control apparatus, in order to protect the power control apparatus itself when the vehicle is involved in a collision.
With the structure described in JP-A-2002-362254 and JP-A-2010-158991, the auxiliary battery is able to be mounted using the space created in front of the motor case, by arranging the detachable structure and the power control apparatus in a location farther back on the motor case toward the rear of the vehicle. However, with a structure in which the auxiliary battery is arranged in front of the motor case, it is necessary to provide a detachable structure that safely moves the power control apparatus that is positioned to the vehicle rear of the auxiliary battery in order to protect and enable rapid discharge of the power control apparatus when the vehicle is involved in an collision, which leads to an increase in cost.